where is pressure guage on vokera option boiler?

I need to add water to up the pressure on my vokera option boiler, I know the pressure guages on these are hidden (where??), I can't find it, and I can't get the front panel off the boiler to look. Have a 1 year old babe trying to sleep in cold and am getting v frustrated. Would be very grateful for any advice (before I take a hammer to the front panel!!) Thank you